Servomotor mounting



Mmh 19, 1940. G. wuNscH 2,194,374

SERVOMOTOR MOUNTING Fiied.Feb. 9, 1939 Patented 19,

SERVOMOTOR, MOUNTING Guido Wnsch, Berlin-Steglitz, Germany, as-

signor to Askania-Werke A. G., a corporation of Germany ApplicationFebruary 9, 1938, Serial No. 189,665

' In Germany February 8, 197

. i; j `i; claims.

This invention relates to improvements relating to servomotors, moreparticularly to servomotors for operating a crank.

Itis an object of this invention to provide an improved arrangement of aservomotor and a crank operated thereby, wherein forces exerted by theservomotor will cause no reaction on the structure on which theservomotor is mounted.

.'I'he present invention is especially useful in installations where aservomotor is to be mounted on light structure and structure of littlerigidity. In aircraft, for example, it has been customary to provide forservomotors for operating control surfaces rigid and heavy supports tobe mounted on the fuselage, as the fuselage on account of its lightconstruction is not able to withstand the Aforces -exerted by theservomotor without substantial deformation.

The present invention aims at providing an improved servomotorarrangement which may be mounted' on very light and even resilientstructure without the aid of a reinforcing base or` support.

Aims, objects, and advantages of this invention will appear from aconsideration of the 'description which follows withthe vaccompanyingdrawing showing for purely illustrative purposes embodiments of thisinvention. It is tobe understood, however, that the description is notto be taken in a limiting sense, thescope of this in vention beingdefined in the Vappended claims. Referring to the drawing:

Fig. l is a plan view of a cylinder and piston servomotor embodying thepresent invention.

Fig. 2 is lan elevation of the device shown in Fis. 1. Fig. 3 isa planview of a rotary servomotor embodying the present invention.

Figbl: is an elevation of the device shown in Fig. 3.

A servomotor cylinder I having trunnions Ii and i2 is mounted foroscillation in intermediate members I3 and i4 for movement about an axisA. The intermediate members I3 and i4 are pivotally mounted in a supportI5 about an axis B, the support being shown as secured to a lightstructure I6.v l Y Pressure iiuid for operating the servomotor isconducted to the cylinder through flexible conduits I1 and Il to act onone or the other side of a ,piston i9 movable in the cylinder it. Apiston rod connects the piston with a crank 2l, va pivotal connectionbeing shown at C. 'I'he crank is rigidly secured to a shaft 22, crankand' shaft being supported for rotation about an axis D by a bearing 23attached to the fundamental structure apart from the support i5 for theservomotor.

In order to prevent reaction forces from being exerted on the supportingstructure rods 24 and 25 vare provided for bracing the. cylinder kill`against the shaft 22. The operation of the device is as follows:

When pressure fluid is supplied through the .the servomotor cylinder IUwere rigidly mounted on the support i5 and the braces 24 and 25 omittedas is the case in conventional. servomotor arrangements, .it appearsthat upon an actuation of the servomotor by supplying pressure fluidthrough the conduit I8 a force would be exerted on thesupport i5 in thedirection of the dotted arrow 5, tending to tear the support ofi" thestructure I6 and deforming the same. It is also apparent that theimproved servomotor arrangement will permit of substantial variationsinthe distance of the axes D and B caused, for example,

by deformations of the structure I6 without causing excessive forces toYbe exerted'by the` servomotor on the structure I6.

A modified form of the invention shown as vapplied to rotary servomotorsis shown in Figs.

3 and 4. In a casing Iiie supplied with pressure fluid at i1' and i8' a.rotary vane I9 is movable which forms expansible chambers 29, with fixedabutments 3|. The housing of the servo' motor ispiyotallyk mounted aboutan axis B in a support IS', the support being secured to a lightstructure i6. To a shaft 26 of the servo'- motor rotated by the rotaryvane I9 acrank 21 is secured operating a second crank 2i' throughv'Jivhe operation of the device is as follows:

When the pressure uid is supplied to the' B and apparentlyslightlyincreasing the weight v of the servomotor. When the distances of theaxes A' and E to the shaft 26 are made equal, that is by making thedistance A'2l equal to the radius of the crank'l, no forces will beexerted on the support i5' in a -direction other than A', B', whereby adeformation of the structure i6' is .eifectively obviated.

Obviously, the present invention is not restricted to the particularembodiments herein shown and described.

What is claimed is:

1. The combination of a servomotor including a cylinder and a piston; afundamental structure; a support attached to a relatively weak part ofsaid structure; 'means for pivoting the cylinder -on said supportaboutfa first axis; a crank and shaft rigidlyconnected Awith each other;a bearing mounted on said structure apart from said support for holdingsaidcrank and shaft turnable about a second axis parallel to said ilrstaxis; a first rod connecting said piston and said crank; and a secondrod connecting said cylinder and said bearing.

2.` 'I'he combination with a servomotor including a cylinder and apiston; a fundamental structure; a support attached to a relatively weakpart of said structure; an intermediate member pivotally connected tosaid cylinder and support. thereby supporting said cylinder; a crank andshaft rigidly connected with each other; a bearing for said crank andshaftmounted on said structure apart fromsaid support; a rst rodconnecting said piston and said crank; and a second rod bracing saidcylinder againstsaid bearing.,

Ei The combination of a cylinder having.a transyerse trunnion;-a pistonmovable in' sfaid cylindr; a fundamental structure; a support attachedto a relatively weak part of' said structure; an intermediate member.pivotally connected to said support vand receiving said trunnion; acrank and shaft rigidly connected with each other; a bearing for saidcrank and. shaftV mounted on said structure apart from said support; afirst rod connecting said piston and said crank; and a second rodpivotally connected to said bearing and 'receiving said trunnion.

4. The combination with arotary servomotor including a casing and ashaft rotatable relatively thereto; of a rst crank secured to the motorshaft; a fundamental structure; a support attached to a relatively weakpart of said structure; means for pivoting said casing Von said supportabout a first axis parallel to thermotor shaft; a bearing mounted onsaid structure apart` from said support; a second' crank mounted in saidbearing for turning about a second axis parallel to the motor shaft;anrst rod connect'- ing said iirstand second crank; and a `second rodpivotally connected with one end to said bearing and with the other endto a point of said' thev servornotor with' said cra ,Y housing, theother second support.

s from the' motor shaft by'a distance approximately equal to the radiusof the iirst crank, whereby the support carrying said casing remainsunadected from the forces exerted by` the motor.

- 5. The combination with a rotary servomotorl including a casing and ashaft rotatable rela-l tively thereto: of a iirst crank secured to themotor shaft; a fundamental structure; a support attached to a relativelyweak part of said structure; means for pivoting said casing on saidsupport about an axis parallel tothe motor axis; a second crank andshaft rigidly connected with each other; a bearing' mountedA on saidstructure 'apart from said SupDOrt for holding said crank and shaftturnable about a second axis parallel to the motor axis; a rst rodconnecting said ilrst and secondA crank; and a second rod'pivotallyconnected with one end to said bearing and with the other end to Vapoint of said casing spaced from the motor shaft by a distanceapproximately Vmotor shaft; a fundamental structure; a support attachedto a relatively weak part of said structure; means for pivoting saidcasing on said support about an axis parallel to the motor axis;

a second crank and shaft rigidly connected with each other; a bearingmounted on said structure apart from said support for holding said crankand shaft turnable about a second axis parallel to th`e motor axis; afirst rod connecting said rst and second :.crank; and a second rodpivotally connected with one end to saidbearing an'd with the other endto a point of said casing spaced from the motor shaft bya distanceapproximately equal to the-radius of the rst crank, whereby the supportcarrying said casing remains unaffected from the forces exerted by the.motor.

7. The combination with a servomotor comprising; a housing and a membermovable thereto; a fundamental structure; a rst support at' tached to arelatively weak part of said structure;

'means for pivoting said housing onvsaid rst supy port about a firstaxis; a second support' attached to saidstructure apart from 'said rstsupport; a y

crank mounted on said second support for turning abouta second axisparallel to said first axis; a rst rod connecting the movable member ofand a second rod of which the one en d is journalled at said end isjournalled at said 8. The combination of a rudder motor for air- -craftcomprising, a housing and a member movable thereto; a support attachedto the fuselage of the craft; means for pivoting said housing on saidsupport about a vfirst axis; a crank and shaft rigidly connected witheach other; a bearing supporting said crank and shaft about a secondmounted on the fuselage apart from said support; a iirst rod connectingthe movable member of the servomo'tor with said crank; and a second rodbracing said housing against said bearing.

, GUIDO WUNSCH.

axis parallel to said rst axis; said bearing being

